1. Field of the Invention
The present invention relates generally to lifting devices, and more particularly, to a wheelchair lift device including a lift car, and having a protective skirt that restricts access below the lift car.
2. Description of the Background Art
Under the Americans With Disabilities Act of 1990 (the “ADA”), the U.S. government required that public buildings be accessible to the disabled. For persons requiring a wheelchair for mobility, abrupt changes in floor elevation have to be modified to enable access by wheelchair. The ADA permits vertical lifting devices to be used instead of a ramp.
Lifting devices for the disabled are known in the prior art. For example, U.S. Pat. No. 5,105,915 (Gary) describes a lifting device having a car including fixed sides and short, one-piece ramps at each end. The car is raised and lowered by a pantograph jack including a hydraulic pump driven by an electric motor controlled by switches. The patent also describes several lifting devices of the prior art. Another wheelchair lifting device is disclosed in U.S. Pat. No. 6,182,798 to Brady, et al., and assigned to AGM Container Controls, Inc., the assignee of the present invention. The '798 patent discloses a portable lift device with gates at both ends of the lift car, transparent walls, a loading ramp, a dock plate, a stage height sensor, and numerous safety features.
Another portable lifting device adapted for wheelchairs is disclosed within pending U.S. patent application Ser. No. 11/026,863, filed on Dec. 30, 2004, and published as U.S. Publ. No. 20060182570 (Zuercher, et al.) on Aug. 17, 2006, also assigned to the assignee of the present application. This application discloses a portable wheelchair lift device that includes a lift car that can be raised and lowered, and which provides protective skirting around the front, back, and sides of the lift device to restrict access below the lift car to help prevent injury.
Applicable governmental regulations require that wheelchair lift devices include a safety skirt surrounding the base of the lift to help keep legs, arms and other body parts from being inserted under the lift car. While such safety skirting is helpful in preventing accidents, the safety skirts are often made from rather flexible, yielding material, such as rubber or plastic. If sufficient force is applied laterally inward upon such safety skirts, they readily give way and deform. Accordingly, were a lift attendant, or even a bystander, to fall against the lift device during operation, such person's legs, arms, head, or other body parts could press sufficiently hard against the safety skirting to cause it to deform. If the lift car is being lowered at such time, there is a possibility that such person's leg, arm, head, etc., could become pinched between the bottom of the lift car and the base of the lift device, posing a significant danger. In view of such dangers, applicable governmental regulations now require that such wheel chair lift devices be able to avoid injury to such persons.
In view of the foregoing, it is an object of the present invention to provide a wheelchair lift device suitable for lifting wheelchair-bound users up to the height of stages, platforms, risers and the like in a safe and reliable manner, and comporting with all applicable ADA requirements.
Another object of the present invention is to provide such a lift device having a safety skirt, and which is able to detect instances when the safety skirt is inwardly deformed to the extent of posing a possible danger.
A further object of the present invention is to provide such a lift device which is capable of halting upward or downward movement of the lift car upon detecting that the safety skirt has been inwardly deformed to the extent of posing such danger.
Yet another object of the present invention is to provide such a lift device achieving the aforementioned objectives without significantly increasing the cost or complexity of the lift device.
These and other objects of the present invention will become more apparent to those skilled in the art as the description of the present invention proceeds.